Optical communication between computing units provides a number of advantages relative to electrical signaling, including increased speed and bandwidth. Such connections often involve using optical fibers or other waveguides. Typically, communication between adjacent printed circuit boards (PCBs) or blades in a computer rack flow along the length of a blade, through a connector into the backplane, through another connector into a switch, and back through a similar path to a destination on the second blade. This process can be relatively slow and require significant electrical power to drive the metal traces and connector pins. Signal integrity and power usage improve through the use of optical communications.
In order to establish more efficient communication between pairs of optical fibers or waveguides, it is valuable to bring the optical channels that transmit light into relatively precise co-axial alignment. For example, single mode optical fibers minimize loss of optical power with an alignment precision of approximately one micron. Multi-mode fibers minimize loss of optical power with an alignment precision within a few microns. It can be difficult to achieve this level of alignment precision between mating assemblies. It is therefore desirable to reduce the needed precision, and to lessen the complexity of the parts and processes used for connecting optical channels.